1. Technical Field
The present disclosure relates to an optical pulse tester.
2. Description of the Related Art
In optical communication systems configured to perform, e.g., data communication with optical signals, optical fibers are used as media for transmitting the optical signals. In, e.g., laying, transferring, and maintenance of the optical fiber, the length of the optical fiber and loss and reflection at a connection portion of the optical fiber are evaluated, for example. Optical pulse testers (OTDRs: Optical Time Domain Reflectometers) are used as measuring instruments. The optical pulse tester emits, as measurement light, an optical pulse to a measurement target optical fiber connected to an optical connector. The optical pulse tester measures, in a time domain, the power of return light (backscattered light and/or Fresnel reflection light) returning to an input end. Moreover, the optical pulse tester displays measurement results, and analyzes the measurement results, for example.
The return light such as backscattered light returns to an input side in a delay time proportional to the distance from a reflection point. The return light forms a characteristic waveform at, e.g., a welded point, a connector connection point, a branching point, a bending point, and a cutting point of the optical fiber. Thus, an event at the optical fiber is detected from the waveform of the power of the return light, the event including, e.g., the welded point, the connector connection point, the branching point, the bending point, and the cutting point. Then, the distance to the event (the position of the event) is measured.
Of optical pulse testers in practical use, an optical pulse tester has various auxiliary functions in addition to the original OTDR function of analyzing the time distribution of the power of the return light. Examples of the auxiliary functions include a stabilized light source function, a visible light source function, an optical power meter function, and a fiber end face inspection function.
FIG. 6 is a view illustrating a menu system of a typical optical pulse tester having a plurality of auxiliary functions. As illustrated in FIG. 6, in the typical optical pulse tester, menu items for calling the function of “OTDR measurement,” a “stabilized light source,” a “visible light source,” an “optical power meter,” or “end face inspection” are displayed as a top screen.
For example, when the “OTDR measurement” is selected, an OTDR measurement screen is displayed. When the “stabilized light source” is selected, a screen for light emission of a light source is displayed. When the “optical power meter” is selected, a screen indicating an input optical power is displayed. A user can select, from the top screen, a menu item of a function corresponding to a measurement purpose to cause the optical pulse tester to execute a desired function.
Examples of documents on this field include JP-A-09-145538.